Electrical contact device



Dec. 28, 1937. c, KOEHLER Re. 20,608

ELECTRICAL CONTACT DEVICE Original Filed May 5, 1934 Reiuuod Dec. 28,1937 UNITED STATES PATENT OFFICE 2am nmc'rmcar. oon'rscr psvrca CharlesH. Koehlcr, on Park, m-

Original No. 2.086,!24Qdated July 6, 1937, Serial No. 724,118, May 5,1934. Application for reissue August 16, 1937, Serial No. 159,442 I Thisinvention relates to electricalcontact devices, and is more particularlydirected to a plu and receptacle connecter which may be used forconnecting and disconnecting an electrical circuit.

In connecting devices of the type in which a multi-contact receptacle ismounted in fixed position, such as on an instrument board, panel, or thelike, and comprises a plurality of plug-receivingor socket membersdisposed in insulated spaced relationship thereon, the problem ofproviding a unit having self-adjusting and aligning characteristics,whereby a corresponding plurality of spaced contact plugs mounted infixed position upon a base or carrier member may be engagedsimultaneously in the receptacle sockets without the necessity ofextremely accurate individualalignment therebetween, presentsconsiderable diflicuity. I

For example, in the use of a disconnecting device for an oil circuitbreaker or the like, wherein a plurality of contacts must be engaged anddisengaged, and wherein spacial requirements de-' mand a compact butsturdy unit, the present invention finds particular application. Thisunit is provided in such an installation to effect conmeeting anddisconnecting of the secondary or control wiring for the breaker, and,since it is mounted, ordinarily, on the side walls of the breakercompartment, it must be compact in design to eliminate, to as great anextent as possible, any interference with the installation and removalof the breaker from the compartment. Further, this control wiringordinarily includes the trip coil circuit for the breaker, and a highgrade, eflicient contact device is thus necessary. Also, because of itsself-aligning characteristics, the present invention is capable of beingemployed in connection with the terminals of the circuit breakersthemselves, since the sockets or terminals of these breakers must beself-adjusting and capable of maintaining equalized contact pressureupon the male contact plugs with which the breaker terminals are engagedwhen the I breaker is moved into operative position. It is to Y beunderstood, however, that the invention is not to be limited to thesespecific uses, since the broad features thereof are applicable invarious other fields.

The present invention, in its preferred embodiment, comprises a pair ofcontact shoes having a ball and socket engagement with a terminal stud,and being enclosed within a floating housing. The contact shoes areurged toward each other and into pressure contacting engagement with :1Claims. (01. 113-332) the terminal studs by means of a pair of spring'members biased-between the outer surfaces of the shoes and the housing.The outer or free ends of the shoes are formed to guide the contact tipof a male contact plug into engagement there- 5 between, and the housingis adapted to extend slightly beyond the peripheral limit of the shoesto enclose fully the entire contact device.

An important object attained by the present invention is the maintenanceof equal pressure between both shoes and the contact tips of the plugand terminal, these contact tips and the inner contact surfaces of theshoes being optionally silver-plated to provide a low resistance andpositive current-conducting path through the contact device. Thisequalization of pressure is obtained by the provision of thefull-floating'housing enclosing the contact shoes and biasing the outerends of the springs,.which bear, at

their inner ends, against the contact shoes. Since the housing iscapable of floating movement, both the contact shoes and housing aremovable about the ball contact tip of the terminal stud, andconsequently the contact shoes are self-aligning with respect to a malecontact plug, due to this uni- 5 versal Joint connection.

An additional object of. the present invention is the elimination of thespring means from anypart of the electrical circuit through the contactdevice, whereby the life of the springs is measur- 3Q ably increased.

Other objects and advantages of the present invention, such as thecompactness and simplicity of. design of the contact device, and itsmanner of assembly in a muiti-point disconnecting unit, '35

will appear more fully from the following de' tailed description which,taken in conjunction with the accompanying drawing, will disclose tothose skilled in the art the particular construction and operation of apreferred form of my inven- 40 Figure 2 is a side elevational view ofthe unit shown in Figure l, with a portion thereof broken away to showin detail the construction of the contact device;

Figure 3 is an enlarged vertical sectional view of the contact deviceshown in Figure 2;

Figure 4 is a sectional view of the contact de-. vice, takensubstantially on the line 4-4 of Figure 3; and

1113111: 5 is, an end view of the contact device and housing, takensubstantially on the line 6-3 of Figure 3.

Referring now in detail to Figures 1 and 2,1 have shown a receptacleunit, indicated generally by the reference numeral I0, and having asubstantially box-like construction terminating in an open facingportion, to which is secured an insulating panel member i2. The panelmember l2 closes the receptacle housing In and, in addition, is providedwith a plurality of stud or pillar members indicated at l3, secured tothe panel i2 and extending rearwardly therefrom to support a secondinsulating panel i4 thereon. I preferably provide six of 'these pillars13, in order to provide adequate support for the secondary panel H, thepillars being provided with spacing bushings for maintaining thesecondary panel ll in spaced relation to the closure panel l2.

Mounted upon the secondary panel M are a plurality of terminal studs,indicated at l5, which extend through the panel and have ball contacttip portions, indicated at I6, and rearwardly extending collar portionsl1 abutting against one face of the panel II. A plurality of nuts I 8are threaded onto each of the studs I5 for securing the same in positionupon the panel ll, there being a washer l9 interposed therebetween. Thenuts II, with the washer i9, form securing means for the terminal endsof a plurality of conductors extending into the receptacle housing Illthrough the opening 20 at the base thereof. These conductors areselectively connected to the various terminal studs I5 within thereceptacle hous ing ID.

As shown, I have indicated eleven of such contact or terminal studs,although it is obvious that any desired number of studs may be employedand arranged symmetrically within the housing. Mounted over the ballcontact tip ii of the plug 15 is a pair of contact shoes 22 and 23,which are preferably formed of forged copper and which are suitablyrecessed to engage about the contact tip l6 and to have universal balland socket connection therewith. The contact shoes 22 and 23 areprovided with a raised centrally located boss portion 26, which isadapted to serve as a seat for one end of a spring member 25, theopposite ends of the spring members 25 being biased against the innerperiphery of a housing 26 which has floating engagement therewith, thehousing 26 being substantially rectangular in shape, as shown clearly inFigure 5, and being of a length so that it extends from the shoulderportion ll of the stud IE to a point slightly forwardly of the forwardends of the shoes 22 and 23, thereby completely enclosing the contactdevice. The housing 26 may be formed of insulating material, as shown,if desired.

The outer ends of the shoes 22 and 23 are beveled outwardly, as shown at21, and are adapted to guide the ball contact tip 28 of a male contactplug or stud 29 into engagement between the shoes 22 and 23. Preferably,the ball contact tip 28, the terminal contact tip l6, and the innercontacting surfaces of the shoe members 22 and 23 are silver-plated, inorder to provide a low resistance contact between these members, andcurrent is transmitted through a path including the contact shoes andthe ball contact tips I6 and 26, therebypreventing any electricalcurrent from passing through the springs 25, which measurably increasesthe life of these springs and allows them to retain their resiliency fora greater period of' The male contact plugs 23 are carried by aninsulating base member 36, which member forms a closure for one race ofthe plug housing 3|. This housing is preferably formed of metal, and isprovided with laterally extending-flange portions 32 and 33 adapted toreceive a pair of diagonally disposed attaching studs 34 having enlargedknurled ends and which extend through the housing 3!, through theinsulating base or closure member 30, through the insulating member l2,and are threaded into corresponding flanged portions 36 of thereceptacle housing II. A pair of countersunk screws 36 are threaded intothe flanges 35 to secure the base member l2 in abutting engagement withthe flanges. A second pair of countersunk screws 36 are threaded intoflanges 32 and 33 opposite the stud openings extending therethrough forsecuring base member 30 to the flanges 32 and 33. The housing 3! maythus be secured in position over and telescoping with the housing Ill,and simultaneously the contact plugs 29 carried by member 30 are engagedwithin the contact shoes 22 and 23. The contact studs 29 are adapted tocarry a plurality 0! nuts 31 threaded onto the projecting ends thereof,these nuts serving to secure conductors to the contact plugs 26, theconductors entering into the housing 3| through an opening 38 formed inthe base thereof.

In the particular type of disconnectunit shown, there are providedeleven contact devices and a corresponding number of contact plugs 23,the plugs 29 being spaced with respect to the base member 30 in the sameposition as the contact devices, and terminal studs I5 are spaced withrespect to the supporting member ll. Thus. upon telescoping engagementof the housing 3i with the housing iii, the plugs are forced throughenlarged openings 46 formed in the closure member i2, and enter thebeveled edges 21 of the contact shoes 22 and 23 and are thereby guidedinto pressure engagement between the contact shoes. Due to the fact thatthe contact shoes have universal movement with respect to the ballcontact tip I6 01' the terminal plug l5, and due to the fact that thehousing 26 has full floating movement with respect to the terminal plug,any slight misalignment between the studs l6 and 29 can be accommodatedby a corresponding movement of the shoes about the ball and socketjoints at the ball contact tips 16. Further, equal pressure will bemaintained, due to the fact that the springs are biased between theshoes and the floating housing, so that upon movement of the shoes thehousing moves therewith, and the spring pressure is maintainedequallyupon both of the shoes.

It is obvious that the invention is equally applicable for other uses,such as for use in connection with circuit breakers, where the contactplugs 29 may comprise the fixed terminals in the switch gear structure,with the contact devices including the shoes 22 and 23, havinginsulating housing 26 thereabout, comprising the socket terminalscarried by the breaker, which are engaged about the plugs when thebreaker is moved into position.

Errther, it is apparent that in place of two contact shoes 22 and 23,any desired number of contact shoes may be provided, the housing 26 insuch instance being formed to take the shape of the outer periphery ofthe contact device, and a plurality of spring means corresponding to thenumber of shoes employed being biased between the shoes and the housing.

It is thus apparent that I have provided an tion requiring theengagement of a fixed male contact plug member within a socket of acontact device, the socket being universally movable to accommodateinaccuracies in alignment between the two contact members;

Having described my invention in accordance with the patent statutes,what I claim as new and desire to secure by Letters Patent is:

1. An electrical contact device comprising a terminal stud having a ballcontact tip, a plurality of contact shoes recessed to have ball' andsocket engagement about said tip and defining a cylindrical openingextending outwardly of said top, an enclosing housing supported aboutsaid shoes, spring means biased against said housing and said shoes, anda male contact plug engageable within the opening formed by said shoes,said spring means equalizing the pressure be- .tween each of said shoesand said contact tip and contact plug.

2. An electrical contact device comprising plurality of contact shoeshaving'universal movement about a fixedball contact member and defininga plug receiving opening, a plug member having a contact portionengageable within said opening, a housing of the same inner peripheralshape as the outer defining periphery of said contact shoes andenclosing the same, and spring means biased against said shoes and saidhousing supporting said housing for conjoint movement with said shoesand normally urging said shoes inwardly for equalizing the contactpressure of said shoes.

3. An electrical contact device comprising a plurality of cooperatingcontact shoes interiorly recessed at one end thereof to define a socketopening, a ball contact member engaged within said socket opening andproviding for universal movement of said contact device thereabout, anenclosing housing about said shoes, spring means bearing against saidshoes and said housing to support said housing in position for conjointmovement of said housing upon movement ofsaid shoes and normally urgingsaid shoes inwardly of said housing about said member, and means at theopposite ends of said shoes for guiding a contact plug into engagementtherebetween.

4. An electrical contact device comprising a ball contact'stud member, aplurality of contact shoes having cooperating recessed portions at oneend engaging about said stud for universal move ment thereabout, theinner surfaces 01! said shoes defining a cylindrical opening forreceiving a contact plug, a housing extending about said shoes, andspring means biased between the outer surface of each of said shoes andthe inner surface of said housing normally urging said shoes inwardly,said housing having free floating support upon said shoes.

5. In combination, an insulating supporting member, a plurality ofterminal studs extending therethrough and having projecting ball contacttip portions, contact devices engaging about each of said contact tipportions, each of said contact devices comprising a plurality ofcooperating contact shoes having ball and socket engagement with saidtip portions, an open-ended housing disposed about said contact shoes,spring means biased between each of said plurality of shoes and saidhousing for supporting said housing thereon,

and a plurality of contact plugs mounted in fixed position on asupporting member and engageable within the. correspondingcontactdevice, said spring means equalizing the pressure contact between saidshoes and said plug.

6. In combination, an insulating supporting member, a plurality ofterminal studs extending therethrough and having projecting ball contacttip portions, contact devices engaging about each of said contact tipportions, each of said contactdevioes comprising a plurality ofcooperating contact shoes having ball and socket engagement with saidtip portions, an open-ended housing disposed about said contact shoes,and spring meansbiased-between each of said plurality of shoes and saidhousing for supporting said housing thereon; and a plurality oi contactplugs mounted in fixd position on a supporting member and engageablewithin the corresponding contact device, said ball andsocket engagementproviding for individual aligning of said contact devices with saidplugs.

7. In combination, a contact plug having a ball contact portion, acontacting device adapted to receive said plug comprising a terminalstud having a ball contact portion, contact means engaged thereabout foruniversal movement with respect thereto. and defining an expansible andcontractible opening for receiving the contact portion of said plug,enclosing housing means disposed about said contact means, and springmeans biased between said housing means and said contact means.

8. In an electric contact device, a plurality of cooperating contactshoes defining a plug-receiving opening, a contact tip projecting from afixed suport and having a rounded contact surface engaged by said shoesand supporting said shoes for universal movement thereabout, anopen-ended enclosing housing for said shoes and fitting thereabout,spring means biased between each of said shoes and the inner surface 01said I housing, and a contact plug adapted to be inserted into saidplug-receiving opening, said shoes and housing being shiftable aboutsaid tip to accommodate axial misalignment between said plug and saidtip.

9. In combination, a supporting member, a contact tip extendingtherethrough and having a spherical contact portion, a plurality ofcontact shoes defining a plug-receiving opening and having concavespherical contact surfaces for cooperating with said spherical contactportion to permitlimited universalmovement about the contact portion ofsaid tip, a second supporting member mounted in spaced parallelalignment with said first supporting member and having an insulatedopening substantially aligned with said plug-receiving opening, acontact plug adapted to be inserted through said insulating opening andengageable within said plug-receiving opening, and means for resilientlyurging said shoes into contacting engagement with said contact tip andsaid contact plug.

1 10. In combination, a ball contact tip, & plurality of contact shoesrecessed to receive said tip and having universal movement thereabout,

spring means engaging said sleeve member and the outer surface 01' saidshoes for urging said shoes inwardlyagainst said tip and plug.

11. In'combination, a ball contact tip projecting outwardly from a fixedsupport, a plurality of shoes having means formed in one end thereof formounting said shoes for universal move- 5 ment about said tip; saidshoes defining at their opposite ends a socket for receiving a malecontact plug, supporting means resiliently carried by said shoes andmovable therewith about said tip, and spring means biased between saidshoes 1-. and said supporting means for urging said shoes toward eachother, said supporting means and shoes being automatically moved aboutsaid tip upon insertion of-a male contact plug thereinto foraccommodating misalignment between said tip and plug.

12. An electrical contact device for connecting a male contact plug to afixed contact tenninal comprising a plurality of contact shoes defininga cylindrical plug-receiving socket at one shoes mounting said shoes foruniversal movement about said fixed terminal, a sleeve enclosing saidshoes and terminating adjacent the ends thereof, and spring means biasedbetween the interior surfaces of said sleeve and the exterior surfacesof said shoes for resiliently urging said shoes into contactingengagement, said sleeve having floating support upon said shoes.

13. In combination, a first insulating supporting member, a contactterminal mounted thereon and projecting from one surface thereof, asecond insulating supporting member extending parallel to and spacedfrom said first supporting member, said second member having an enlargedopening substantially in alignment with said terminal and adapted toreceive a projecting male contact plug, and means for establishingconnection between said plug and said terminal comprising a pair ofcontact shoes, a sleeve of less axial length than the space between saidsupporting members enclosing said shoes, means biased against theinterior lateral surface of said sleeve for urging said shoes intocontacting engagement between said plug and terminal, and means at oneend of said shoes providing for universal movement of said shoes andsleeve about said terminal.

14. An electrical connector comprising, in combination, a first contactmember having a convex 50 spherical contact portion, a. plurality ofcontact shoes each having at one end a concave spherical contact portionfor contact engagement with said convex spherical contact portion andhaving at the other end a concave cylindrical contact por- 5:, tion forcontact engagement with the convex spherical contact portion of a secondcontact member, and resilient means biasing said contact shoes intocontact engagement with the spherical contact portions of said first andsecond contact members.

15. An electrical connector comprising, in combination, a first contactmember having a convex spherical contact portion, a plurality of contactshoes each having at one end a concave spherical contact portion forcontact engagement with said convex spherical contact portion and havingat the other end a concave cylindrical contact portion for contactengagement with the convex spherical contact portion of a second contactmember, support means encircling said contact shoes, and resilient meansacting between said support means and said contact shoes for biasingthem into contact engagement with the spherical contact portions of saidfirst and second contact members.

16. An electrical connector comprising, in comend thereof, means at theopposite end of said bination, a first contact member having a convexspherical contact portion, a plurality of contact shoes, each having atone end a concave spherical contact portion for contact engagement withsaid convex spherical contact portion and having at the other end aconcave cylindrical contact portion for contact engagement with theconvex spherical contact portion of a second contact member, supportmeans encircling said contact shoes, and resilient means individual toeach of said contact shoes and acting between said sup port means andsaid contact shoes for individually biasing them into contact engagementwith the spherical contact portions of said first and second contactmembers.

17. an electrical connector comprising, in combination, a first contactmember having a convex spherical contact portion, a plurality of contactshoes each having at one end a concave spherical contact portion forcontact engagement with said convex spherical contact portion and havingat the other end a concave cylindrical contact portion for contactengagement with the convex spherical contact portion of a second contactmember, support means encircling said contact shoes, resilient meansindividual to each of said contact shoes and acting between said supportmeans and said contact shoes for individually biasing them into contactengagement with the spherical contact portions of said first and secondcontact members, and means on each of said contact shoesfor centeringsaid resilient means thereon.

18. An electrical connector comprising, in combination, a pair of spacedapart contact members having convex spherical contact portions, aplurality of contact shoes arranged and adapted to interconnect saidcontact members by contact engagement with said convex spherical contactportions thereof, support means encircling said contact shoes, andresilient means acting between said support means and said contact shoesfor biasing them into contact engagement with said convex sphericalcontact portions of said contact members.

19. An electrical connector comprising, in combination, a pair of spacedapart contact members having convex spherical contact portions, aplurality of contact shoes arranged and adapted to interconnect saidcontact members by contact engagement with said convex spherical contactportions thereof, support means encircling said contact shoes, andresilient means individual to each of said contact shoes and actingbetween said (support means and said contact shoes for individuallybiasing them into contact engagement with said convex spherical contactportions of said-contact members.

20. An electrical connector comprising, in combination, a pair of spacedapart contact members having convex spherical contact portions, aplurality of contact shoes arranged and adapted to interconnect saidcontact members by contact engagement with said convex spherical contactportions thereof, means preventing detachment of said contact shoes fromone of said con tact members, said contact shoes being readilydetachable from the other of said contact members, support meansencircling said contact shoes, and resilient means individual to each ofsaid contact shoes and acting between said support means and saidcontact shoes for individually biasing them into contact engagement withsaid convex spherical contact portions of said contact members.

tact members, said contact shoes being readily 10 detachable from theother of said contact memso,oos 5 bers, support means encircling saidcontact shoes. resilient means individual to each of said contact shoesand acting-between said support means and said contact shoes forindividually biasing them into contact engagement with said convex 5spherical contact portions of said'contact members, and means on each 0!said contact shoes for centering said resilient means thereon.

CHARLES H. KOEHLER. 10

